A hydraulic excavator, a bulldozer, and the like, each of which includes a crawler belt, have been known as work vehicles. The crawler belt includes a belt-like crawler belt link chain in which a plurality of crawler belt links are coupled to one another. By coupling crawler belt links at the ends of the belt-like crawler belt link chain to each other, an endless crawler belt is obtained. The endless crawler belt is wound around a traveling apparatus. The traveling apparatus includes a driving wheel, an idler tumbler, a track frame, and the like. As an apparatus for coupling the end portions of the crawler belt link chain to each other, a special crawler belt pin or a special crawler belt link is used. The former is called a “master pin”, and the latter is called a “master link”. The crawler belt may be detached/attached from/to the traveling apparatus in order to exchange wear-out parts or the like. When detaching/attaching the crawler belt from/to the traveling apparatus, the crawler belt link chain needs to be decoupled/coupled.
In the case where the master pin is used as the coupling apparatus, the master pin needs to be detached/attached to/from the crawler belt link so as to decouple/couple the crawler belt link chain. In general, the master pin is press fitted into a through hole of the crawler belt link. Hence, for the detachment/attachment of the master pin, a pressing machine is required. Thus, such a pressing machine is required to detach/attach the crawler belt from/to the traveling apparatus in a work site for the work vehicle. Accordingly, time and effort are required to prepare the pressing machine in the operation of detaching/attaching the crawler belt in the work site. This results in poor workability.
In order to save the time and effort, for example, Japanese Utility Model Laying-Open No. 64-1078 (Patent Document 1) proposes an apparatus permitting detachment/attachment of a master pin from/to a crawler belt link and including a retaining pin to prevent the master pin from coming off from the crawler belt link. In this structure, the retaining pin is withdrawn/inserted to detach/attach the master pin from/to the crawler belt link without using a pressing machine.
In addition, in this apparatus, a brim is provided at one end of the master pin and the retaining pin is inserted into the other end thereof. Further, the crawler belt link is provided with a locking boss, which is engaged with the brim of the master pin. With the engagement between the brim of the master pin and the locking boss of the crawler belt link, the master pin can be suppressed from being turned according to the crawler belt link.